InGaN/GaN light emitting diodes grown on nanoimprint-based hollow-patterned sapphire substrates

Abstract In this study, conical-shaped hollow-patterned sapphire substrates (HPSSs) with three different sizes, were fabricated and used as substrates for blue light emitting diode (LED). The HPSSs were fabricated on 2-inch diameter sapphire wafers by nanoimprint technique. Blue LED structures were grown on the HPSS and flat sapphire wafer, in order to investigate the effect of hollow patterns on sapphire substrate. The photoluminescence (PL), electroluminescence (EL) and X-ray diffraction analysis were used to characterize the blue LED structures. Luminescence efficiency of LED structure, grown on HPSS wafer was improved, compared to identical LED structure grown on conventional flat sapphire wafer. 4.5 times stronger PL and 1.7 times stronger EL intensities were observed from GaN based LED structures grown on HPSS.